Composition-based tools provide the ability to screen potential whole crude oils or partial crude fractions for plant test runs and subsequent base oil quality evaluations by providing predictions of the potential product qualities and/or yields that may be expected from a feedstock. Composition-based tools typically require detailed compositional characterization of a potential feedstock to ensure proper prediction accuracy.
A possible use of composition-based tools for prediction of product properties is in analysis of potential feeds for lubricant base oil production. Unfortunately, the ability to predict product yields and/or properties using currently available composition-based tools is limited. For example, viscosity index (VI) is an important product quality for determining the value and/or usage of a lubricant product. Current composition-based models, however, are unable to consistently provide accurate predictions of the potential VI values for lubricant base oils that can be made from a feedstock. Because conventional composition-based models are not reliable, analysis of a crude oil feedstock (or a feedstock containing a mixture of crudes) to determine suitability for lubricant base oil production is currently based on performing a full assay of the feed. Performing an assay for lube production potential can require a sample size on the order of hundreds of liters and can further require several months of time. It would be desirable to have a method for determining potential VI values for lubricant based oils produced from a feedstock that can be performed on a significantly shorter time scale.
U.S. Pat. No. 6,317,654 describes use of composition-based models for prediction of properties for finished lube products formed from a feed. After performing a characterization of a potential feed, the characterized potential feed can be compared with other feeds in the composition based model to identify similar feeds. Predictions of base oil properties for the potential feed can then be made based on compositional model. The predicted properties include thermal and oxidation stability of finished products formulated from base oils derived from processing of a feed.
U.S. Pat. No. 8,992,770 describes a method for characterizing crude oils as potential feedstocks for production of lubricant base oils. A potential feedstock can be characterized based on isoparaffin content and dewaxed distillate viscosity index to determine the suitability for use in lubricant base oil production. Feedstocks with a dewaxed distillate viscosity index at a pour point of −9° C. of less than 0 are described as being less favorable for use in lubricant base oil production.
U.S. Patent Application Publication 2010/0070202 describes a method for predicting low temperature properties of a formulated lubricant oil based on characterization of the corresponding base oil. The low temperature properties are predicted based on characterization of the base oil using Differential Scanning Calorimetry (DSC).